26 Tannin in the Fruit of the Persimmon [Sept 



membrane forrned in a watery preparation grow after the manner 

 of a copper sulfate-potassiiim ferrocyanid membrane, and assume 

 remarkable dimensions, having the appearance of a veil over the 

 protruding tannin-mass (fig. 13). Such membranes are formed 

 with great readiness if the pnlp of a soft, edible but not overripe 

 persimmon be mixed with, say, an eqnal bulk of water. If such 

 a mixture be allowed to remain a long time so that fermentation, 

 following the entrance of organisms, may proceed, the tannin- 

 masses and these granulär membranes will remain unaffected. 

 They are, indeed, imputrescible tannin-compounds. I have found 

 them to be more resistant to dilute acids than the tannin-mass itself, 

 still maintaining their integrity after the complete hydrolysis of 

 the latter. It seems therefore that the whitish granulär matter in 

 question is formed by chemical union of the escaping soluble tannin 

 with a substance without the tannin cell, probably the pectose 

 derived by digestion of the middle lamella. In support of this 

 view, I offer evidence beyond. 



We now examine the tannin-cell when it has reached a condi- 

 tion which, on adding water, is characterized by swelling sufficiently 

 to Stretch the cell wall, and even to rupture it, usually without the 

 extrusion of the tannin-mass itself. The kind of result following 

 exposure to water depends on whether a single cell or a small group 

 is flooded or whether a larger mass of cells is merely surrounded 

 with water. In the former instance, the rapid swelling may cause 

 a rupture in the wall, preceded by the earlier described internal 

 compression of the protoplasm and its vacuoles. By the use of a 

 very dilute ferric acetate Solution, I was able to watch the explosion 

 of such a cell, when there was expelled a puff of tannin, which 

 immediately formed a delicate blue spherical cloud at some distance 

 from the opening. There was no extrusion of the tannin-mass. 

 In another case, such an extrusion was observed to occur after the 

 initial expulsion of tannin. If only a small amount of water be 

 added to the preparation, so that the tannin-cells are in effect sur- 

 rounded by the Solution of pectose, or if they are mounted in fruit 

 Juice alone, a different behavior ensues. The swelling of the 

 tannin-mass may now take place gradually, and the free tannin 

 escapes under pressure from within by one or more minute pores 



